Ohai . III. DIGITALIS PURPUREA. 81 



generation ; and the seedlings from these crosses were 

 grown in competition with self-fertilised plants of the 

 two corresponding generations. In the first trial the 

 intercrossed plants were less fertile than the self- 

 fertilised, and less tall in the ratio of 100 to 110. 

 In the second trial, the intercrossed plants were more 

 fertile than the self-fertilised in the ratio of 100 to 

 73, and taller in the ratio of 100 to 92. Notwith- 

 standing that the self-fertilised plants in the second 

 trial were the product of two additional generations 

 of self-fertilisation, I cannot understand this discor- 

 dance in the results of the two analogous experiments. 



The most important of all the experiments on 

 Mimulus are those in which flowers on plants of the 

 eighth self-fertilised generation were again self-ferti- 

 lised ; other flowers on distinct plants of the same lot 

 were intercrossed ; and others were crossed with a new 

 stock of plants from Chelsea. The Chelsea-crossed 

 seedlings were to the intercrossed in height as 100 to 

 56, and in fertility as 100 to 4 ; and they were to the 

 self-fertilised plants, in height as 100 to 52, and in 

 fertility as 100 to 3. These Chelsea-crossed plants 

 were also much more hardy than the plants of the 

 other two lots ; so that altogether the gain from the 

 cross with a fresh stock was wonderfully great. 



Lastly, seedlings raised from a cross between flowers 

 on the same plant were not superior to those from 

 flowers fertilised with their own pollen ; but this result 

 cannot be absolutely trusted, owing to some previous 

 observations, which, however, were made under very 

 unfavourable circumstances. 



Digitalis purpurea. 

 The flowers of the common Foxglove are proterandrous ; that 

 is, the pollen is mature and mostly shed before the stigma of 

 ihe same uowcr is ready for fertilisation. This is effected by 



Q 



